A、<span style=";font-family:微软雅黑;font-size:15px"><span style="font-family:微软雅黑">固定不变</span></span></p><p></p>
B、<span style=";font-family:微软雅黑;font-size:15px"><span style="font-family:微软雅黑">都在逐渐减少</span></span></p><p></p>
C、<span style=";font-family:微软雅黑;font-size:15px"><span style="font-family:微软雅黑">互相转化</span></span></p><p></p>
D、<span style=";font-family:微软雅黑;font-size:15px"><span style="font-family:微软雅黑">逐渐递变</span></span></p><p></p>